1. Field of the Invention
The invention relates to an imaging apparatus that performs auto-focus (AF) based on a group of in-focus conditions and a method of automatically setting the in-focus conditions.
2. Description of the Related Art
Many digital cameras are configured to automatically focus by using a method of performing auto-focus (AF) such as contrast measurement so that users may take a photograph without having to manually focus. Often, auto-focus is initiated by the user half pressing a shutter button. Methods of performing AF often use a group of in-focus conditions to evaluate how focused an image is. The in-focus conditions may include conditions that indicate that only a portion of the image such as whether or not a subject included in the image is in focus, and whether or not a particular area of the subject such as the face is in-focus. Often, the AF method controls the lens and iris. The AF method may move the lens through a range of positions to find a position with a high AF value, which is calculated using the in-focus conditions. Once the AF method finds the position with the high AF value, the user may capture an image if the user finds the image pleasing. Often the user captures the image by fully pressing the shutter button.
The in-focus conditions that are used by the AF method may not be the in-focus conditions that a user prefers. For example, the in-focus conditions may heavily favor weighting an area of the image that includes a subject's face when the user of the digital camera would prefer that more weight be given to a larger area of the image such as a group of people.
The AF method will position the lens and iris in different positions and thus produce different images depending on the in-focus conditions. Some in-focus conditions will produce images that are more pleasing to a particular user than other in-focus conditions. One camera is configured to measure how pleasing an image is to a user in the following way. An external sensor is attached to the user that senses a psychological state of the user. The sensor transmits the psychological state to the camera. The camera then can determine how pleased a user is by using the information from the external sensor attached to the user. The camera then measures the psychological state of the user after an image is displayed on a viewer of the camera and adjusts the in-focus conditions to try and produce images that are more pleasing to a user.
However, external sensors may increase the cost of the camera and be inconvenient for the user to wear.